Electrical connecting spring device



Sept. 16, 1969 w. H. wALLo 3,467,940

ELECTRICAL CONNECTING SPRING DEVICE Filed March 17, 1967 .ATTORNEYSUnited States Patent O U.S. Cl. 339--14 11 Claims ABSTRACT OF THEDISCLOSURE A coiled compression spring mounted in a separable plug andjack connector automatically expands and grounds the plug in the absenceof the jack and is inactivated upon being compressed by assembly of thejack with the plug.

This invention relates to the art of electrical connecting devices, andis more particularly concerned with a compression spring device whichautomatically makes an electrical connection between two electricallyconductive elements in the expanded condition of the springiand isinactivated upon being compressed.

An example of electrical mechanism in which an automatic electricalconnection is necessary in one vcondition of the mechanism and adisconnection or inactivation is necessary in another condition of themechanism, is in that type of electrical connection known as a phonoplugconnector which provides a low cost means for connecting two circuitstogether or two pieces of apparatus together without requiring asoldered connection. This type of connector is efficiently utilized intelevision sets having `both VHF and UHF tuners. The jack portion of theconnector is suitably connected to the VHF tuner, and the plug portionof the connector is attached to a section of armored cable which issoldered directly into the UHF chassis. Part of the UHF tuner circuitryis a conversion crystal which is highly sensitive to buildup of staticcharges. Such charges are liable to develop when the connector isseparated. Therefore, means are provided for grounding the plug,connected to the UHF tuner, when the plug is pulled out of the socket ofthe jack portion of the connector.

As heretofore effected, grounding of the plug has been by means of atension spring connected to the grounded cable armor and normallythrusting toward the plug, to be displaced laterally when the plug isinserted into the mating socket or jack. Such a spring has been anexpensive component, costly to install, and unduly susceptible todamage.

An important object of the present invention is to pro vide new andimproved electrical spring means which will overcome the disadvantagesand deficiencies of the prior constructures and Which will affordnumerous advantages including lower cost, ease of installation,practical freedom from damage, and highly eicient performance.

Another object of the invention is to provide substantially improvedmeans for effecting selective electrical connection and disconnectionbetween electrically conductive members.

A further object of the invention is to provide a new and improvedspring means for automatically electrically connecting conductiveelements in a separable connector when the separable members of theconnector are separated and which will automatically disconnect uponassembly of the separable members of the connector.

Other objects, features and advantages of the present invention will bereadily apparent from the following detailed description of certainpreferred embodiments thereof taken in conjunction with the accompanyingdrawing, in which:

3,467,940 Patented Sept. 16, 1969 FIGURE 1 is a side elevational view ofan electrical connector embodying features of the invention;

FIGURE 2 is an enlarged longitudinal sectional detail view through theconnector of FIGURE l;

FIGURE 3 is a separated assembly view of the separa-- ble members of theconnector, with certain parts broken away and in section to show detailsof structure;

FIGURE 4 is a transverse sectional detail view taken substantially online IV-IV of FIGURE 2;

FIGURE 5 is a top plan view of the compression shorting spring of theconnector shown in its normal biased or expanded condition;

FIGURE 6 is a side elevational view of a modification of spring; and

FIGURE 7 is a plan showing the spring of FIGURE 6 in its compressedcondition.

An example of a jack and plug connector, of the kind referred to in thetelevision industry as a phonoplug, is shown in FIGURES 1-3 andcomprises a plug assembly 10 and a jack assembly 11. In this instancethe plug assembly 10 is especially devised to be connected to an UHFtuner in a television set while the jack assembly 11 is arranged to beelectrically connected to the VHF tuner of the set.

Component elements of the plug assembly 10 comprise an electricallyconductive hollow tubular plug 12 mounted on a dielectric disk 13 whichsupports in insulated relation about the plug an electrically conductiveshell 14 providing a connector retaining sleeve longitudinally slottedto provide resilient gripping fingers 15. Into the base end portion ofthe plug 12 is adaptedto be inserted the end portion of an insulatedelectrical cable 17, having the end portion of its electrical lead 18electrically attached to the plug as by means of solder 19. The cable 17is of the armored type having a grounding electrically conductive armorsheath 20 which is electrically attached to the shell 14 as by means ofsolder 21.

Component elements of the jack member 11 comprise an electricallyconductive tubular socket 22 complementary to the plug 12 to receive theplug in electrically connective slidable relation therein and having arearwardly extending solder lug 23 for electrical attachment thereto ofa connecting electrical cable. Mounted about the socket tube 22 is adielectric sleeve 24 which supports a tubular connector shell 25 ininsulated relation about the socket and of a diameter to sit in snugretained relation when pressed into the retaining fingers 15 of the plugassembly. A lead-in bore 27 aligned with the lead-in end of the socket22 is provided by a dielectric disk 28 supported by the front endportion of the shell 25. Through this arrangement, ready connection andseparation of the plug 10 and the jack 11 are adapted to be effected byfrictionally coaxially pressing them together or pulling them a art.

pMeans `are provided for effecting an electrical connection between theplug element 12 and the shell element 14 whenever the connector membersare separated, and for automatically breaking such electrical connectionwhen the connector members are assembled in their operative relationAccording to the present invention such means comprise an electricallyconductive compression spring 29 normally biased to eiect the electricalconnection between the elements 12 and 14. For this purpose, the spring29 is of spiral form comprising a relatively large base loop 30 at oneend, a relatively smaller loop 31 at its opposite end and a connectingportion 32 which normally biases the loops into spaced apart relativelyeccentric relation. The large loop 30 is of a diameter substantiallycomplementary to the inside diameter of the connector shell 14 to bereceived therein in snug slidable electrically connected relation, withthe spring encompassing the plug 12. The small loop 31 is of a size toreceive the plug 12 therethrough freely, and the biased eccentricity ofthe small loop 31 is such that in the normally biased, expandedcondition of the spring 29 the small loop slidably engages the plug 12in iirm electrically connecting relation as best seen in FIGURES 3 and5.

When the plug member and the jack member 11 are assembled to effect anelectrical connection, the jack member 11 compresses the spring 29toward the base provided by the dielectric element 13. As a result theloop 31 and the connecting portion 32 of the spring assume asubstantially regular spiral relationship to the large loop 30, whereinthe small loop 31 is substantially concentric with the large loop, andthereby also assumes a substantially concentric, spaced relation to thestem or plug 12, as shown in FIGURES 2 and 4. Thus, automatically onassembling the connector members 10 and 11 operatively, the electricalconnection between the elements 12 and 14 is broken. Conversely,automatically upon separating the members 10 and 11, an electricalconnection is made between the elements 12 and 14 by expansion of thespring and movement ot the small loop into its biased eccentricplug-engaging relation. In order to avoid electrical contact of thesmall loop 31 in its compressed condition with a retaining crimp collar33 on the base of the plug 12, a dielectric insulating disk 34 isinterposed between the base loop 30 of the spring 29 and the collar 33.

By having the connecting portion 32 of substantial length, a range oflongitudinal sliding electrical engagement of the small loop 31 with thepost or plug 12 is attainable as the jack 11 is pulled from the plugassembly 10. For example, the eccentric and longitudinal biasing effectof the connecting portion 32 may be such as to provide for biasedcontact of the small loop 31 with the plug 12 after only partialWithdrawal of the jack 11 from the receptacle shell 14 and thenprogressive outward longitudinal sliding of the small loop along theplug, with progressively increasing eccentric biasing pressure, as jackseparation continues. The small loop 31 thus effects a self-cleaning,working-in rubbing, electrical contact assuring circuit makingVconnection with the engaged surface of the plug 12 in advance ofelectrical separation of the plug and jack. This affords a valuableIsafety factor in a critical situation where positive assurance ofelectrical connection and absence of potential buildup or sparking isdesirable.

Where a shorter spring is desired, and longitudinal sliding along thepost is not important, or instantaneous make/break contact isadvantageous, the spring 29 of FIGURES 6 and 7 may be used. Thisarrangement may be such that by having the connecting portion 32' of arelatively short length between the larger base loop 30 and the smallereccentrically biased loop 31', a swinging movement of the small loop 31between its collapsed and its biased expanded positions is effected, asindicated by the directional arrow in FIGURE 6. Thus, in the compressedcondition of the spring, the smaller loop 31' swings intocircuit-breaking relation away from the plug 12 and into generallyconcentric relation thereto as shown in full outline in FIGURE 7. Whenthe spring is released, the connecting portion 32 swingingly biases thesmall loop into the electrical circuit making contacting relation to theplug 12, as shown in dash outline in FIGURE 7 and as indicated in thefull outline position of the small loop 31 relative to the dash outlineshowing of the plug 12 in FIGURE 6.

In both forms of the spring 29 and 29', it will be appreciated that alow cost, effective electrical connection spring device has beenprovided. Low cost is attained in one respect because the simple spiralstructure of the' spring is the most economical compression spring froma manufacturing standpoint since it is free from any special or peculiarbends requiring complicated die structures to produce. Further, utmosteconomy in mounting the spring with the connector plug assembly isattained because all that is necessary is to thrust the spring intoposition within the receptacle provided by the connecting shell of theplug assembly which thus requires no special tooling or machining,crimping or special connecting means for mounting the spring. Further,the spring is thoroughly protected within the receptacle shell againstcatching on extraneous objects or being otherwise liable to damage inhandling, packaging or in use of the associated plug. Since the springis so thoroughly protected against damage or maladjustment, it is highlyreliable for its intended functions.

It will be understood that variations and modifications may be effectedwithout departing from the spirit and scope of the novel concepts ofthis invention.

I claim as my invention:

1. In an electrical assembly having insulated electrically conductiveelements laterally offset from one another along an assembly axis andadapted to have a member relatively movably cooperative therewith alongsaid axis:

an electrically conductive compression spring mounted in associationwith said elements and normally eccentrically biased to eiect anelectrical connection between said elements;

said spring being compressible by movement of said member in onedirection relative to said elements to break said electrical connection.

2. An electrical assembly as defined in claim 1, in which said spring isof spiral construction having one portion thereof in permanentelectrical connection with one of said elements and a second portionwhich is movable eccentrically relative to said rst portion intoelectrical engagement with the other of said elements in the biasedcondition of the spring and is movable away from said second elementtoward said first portion when the spring is compressed by movement ofsaid member.

3. An assembly as defined in claim 1, comprising a connector plug memberin which said elements comprise respectively a plug adapted to have anarmored cable electrically attached thereto and the other of theelements comprising a receptacle shell adapted to have the armor sheathof the cable electrically attached thereto, dielectric base meansconnecting the plug and receptacle in insulated relation, saidcompression spring being helical and having a large base loopelectrically engaged within said receptacle concentric with the plug andhaving a smaller loop which is of larger diameter than the plug and hasthe plug extending therethrough, and a connecting portion of the springbetween said loops normally biasing the smaller loop into eccentricrelation relative to the larger loop and into electrically contactingrelation against the plug.

4. An assembly as defined in claim 3, in which said connecting portionis of a length to effect longitudinal sliding engagement with the plugas the spring is released from its compressed condition.

5. An assembly as deiined in claim 3, in which said connecting portionis relatively short such that the smaller loop moves in a swingingrelation relative to the larger loop between the compressed and normallybiased conditions of the spring.

6. An assembly as defined in claim 1, in which one of said elementscomprises an elongated member, the other of said elements comprises areceptacle shell about said elongated member, a dielectric basestructure mounting said elements in spaced relation, said elongatedmembei' including a larger diameter shoulder collar engaging said basestructure within the receptacle of said shell; said spring being ofcoiled helical form about the elongated member and having a relativelylarge loop engaging the shell within the receptacle adjacent to the basestructure substantially spaced from the elongated member and a smallerloop normally biased into eccentric spaced relation to the larger loopand into engagement with said elongated member but movable out ofengagement with the elongated member upon compression of the spring, anda dielectric spacer between said spring and said collar to avoid contactthereof by the smaller loop during said compression.

7. For use in an electrical assembly having insulated electricallyconductive elements adapted to have a member relatively movablycooperative therewith:

an electrically conductive compression spring having a relatively largeloop-like portion adapted to be in electrical contact with one of saidelements and a relatively movable portion with an integral portionconnecting them; said connecting portion normally .biasing said movableportion relative to said loop-like portion to make electrical connectionwith the other of said elements;

and said movable portion moving into electrical connection-breakingrelation to said other element by compressing the spring.

8. A spring as defined in claim 7, in which said looplike portion andsaid relatively movable portion are respective differential diameterloops of a helically coiled spring, and said connecting portion is ofsubstantial length and the loops are movable thereby into substantialaxially spaced apart eccentric relation in the normally biased expandedrelation of the spring.

9. A spring as defined in claim 8 in which said relatively movableportion loop has a substantial range of longitudinal and eccentricmovement between the normal biased and compressed relations ofthespring.

10. A spring as defined in claim 7, in which said connecting portion isrelatively short such lthat said movable portion swings between itsnormally biased relation and a compressed relation to said loop-likeportion.

l1. ln an electrical assembly comprising an electrically conductivereceptacle and an electrically conductive plug within said receptacleand insulated therefrom and adapted to have a member relatively movablycooperative therewith:

an electrically conductive spiral compression spring having a relativelylarge .base loop permanently engaged with the receptacle electricallyand having a smaller loop, with a connecting portion between said loopsnormally biasing the smaller loop into engagement with said plug toeffect an electrical connection between said receptacle and said plug;said spring being compressible by movement of said member in onedirection relative to said receptacle and plug to break said electricalconnection.

References Cited UNITED STATES PATENTS 2,664,475 12/ 1953 Harlin20G-51.1 2,825,882 3/1958 Mitchell 339-19 XR FOREIGN PATENTS 899,622 6/1962 Great Britain.

MARVIN A. CHAMPION, Primary Examiner PATRICK A. CLIFFORD, AssistantExaminer U.S. Cl. XR.

339--A-19, 177; 200-5l.l

